Two years ago, at 48, Donna was diagnosed with early-onset Alzheimer's disease, which, despite all the studies, is still a mystery in many ways. Spouses and children, along with doctors and caregivers, watch their loved ones decline for years, wondering whether they know what they have forgotten, or whether they are suffering or sad.

Donna knows those answers and wants to explain. She has a precious window of time, partway between the Donna she used to be and the Donna who won't remember her. She wants to tell her story while she still knows it is hers.

There isn't much time.

Already, in a restaurant, she can't always find her way from the restroom back to the table.

She tried holding tight to the whip-smart Donna who spent 20 years in banking, handling as many as 10 mortgage loans a day, the paperwork inches thick, but today Donna can't add a column of numbers.

The Donna who loved to read, often finishing a book in a day, has faded, too, leaving a shelf of books unread, and the Donna who's here now can't follow three paragraphs into a novel.

Donna always knew her own mind, and yet she is helpless to keep it from dissolving.

"People have to pay attention. It's not an old person's disease. It destroys who you are and everyone around you," she says. "It kind of takes away everything that makes you you. I am losing my life with my husband. He's losing me a little at a time."

Donna's husband, Nick, leans into his wife.

"It changes by the day," he says. "She'll get up one day and she can't do something she could do the day before. And that's tough to watch, and then she may be fine for three months. It's just really hard to watch her struggle through all this."

There is little they can do. Doctors don't have a real understanding of how Alzheimer's occurs, or why. There is no preventing it and no stopping it. After three decades of research and hundreds of drug trials, only a handful of medicines are available -- and those don't actually slow the progression of the disease, which continues its assault on the brain; they only temper some of the dementia symptoms for a while.

The only consolation, Donna says, is that "it is slow."

"I don't think it is so slow," Nick interjects softly, and looks down at the tablecloth, tears in his eyes. His wife wraps her arms around him.

First signs

It was a little more than three years ago that Nick first noticed Donna's memory slipping, which was alarming since her memory had always been amazingly good, far better than his.

"She was my memory," Nick, who's 56, says.

He could ask her the name of a doctor he had seen two years earlier, and she could tell him not only the doctor's name but the phone number and location of the office.

But then his wife started asking Nick for information, including the name of that doctor. And the Donna who drove herself to Arizona from New York 14 years ago, who loved to jump into the car on weekends to explore the state without a map, began getting lost.

On the way to the store. And, after that, on the way back from her sister's house, 2 miles from her own Peoria house and a trip she'd made hundreds of times.

Nick wanted her to go to the doctor. But Donna didn't think she needed to. A vegetarian since age 17, a runner, a woman who took vitamins, never smoked and hardly ever drank, felt fine.

"I've never had anything wrong with me," she says.

But a routine vision test in November 2008 showed something was wrong. Donna thought maybe she needed glasses. But her field of vision was narrowing drastically, though the ophthalmologist could not see a reason why. There was no damage to the eye. No glaucoma or torn retina.

Donna saw a retinal specialist and then another ophthalmologist, and still no answers. In June 2009, she was referred to Sharon Johnstone, a neuro-ophthalmologist at St. Luke's Medical Center in Phoenix, who ran more tests and then sent Donna for an MRI to rule out a blockage, tumor or aneurysm.

"You'd almost welcome that -- something treatable. I would have thought, 'OK, I've got a shot with that,'" Donna says.

But the image showed atrophy, a wasting away of tissue, in the part of her brain that controls vision, a problem unexpected at Donna's age.

Johnstone sent Donna for a neuro-psychological evaluation at Barrow Neurological Institute at St. Joseph's Hospital and Medical Center in September 2009. It consisted of a series of simple tasks: Can you draw a clock? Count backward by sevens? Repeat five words in the same order?

"You're like, 'whatever,' and then you go to do it, and you can't," Donna says.

In the room, there was silence, empty and long, as she strained to find the information in her brain.

"I was frustrated and angry and embarrassed. I'm an intelligent woman; why can't I do something a grade-schooler could do?" Donna says.

Could she recite five words that start with the letter R? Donna tried cheating, looking around the room for clues.

"I looked all around, looked down. Aha, rug!" she says. "But I couldn't think of it on my own."

Donna could recall two of the five words: "There were three more? Seriously? It was like my head had turned into a solid concrete block. There was nothing going on. Not an 'oh, what was that again?' feeling. Just gone."

Johnstone then referred Donna to neurologist Stephen Flitman. In October 2009, more tests brought no better news. A PET scan of her head showed that her brain was shrinking, even pulling away slightly from her skull in places.

The result was unusual in someone of Donna's age, although Flitman has diagnosed patients as young as 39. Typically, people diagnosed with Alzheimer's are in their 60s and 70s; anyone diagnosed with the disease earlier than 65 usually is considered an early-onset case.

In his medical notes, Flitman wrote that, without doing genotyping, his confidence in his diagnosis was 90 percent. Because it is expensive, and because Donna has no biological children to caution in the event that the disease is genetic, the Bakers had decided against genotyping.

Despite the episodes of confusion, her changing vision, the long year of testing, her failure at simple evaluation tasks and the doctor's diagnosis, Donna clung to the hope of that other 10 percent.

"I didn't want to believe that was what was wrong with me," she says.

During that first year, Donna tried to learn everything she could about the disease, hoping she would find something that would indicate she didn't have it.

Experts think several gene mutations may contribute to Alzheimer's in younger people, and early-onset Alzheimer's can run in families. But Donna has no known family history of dementia. Her mother died at 55 of a stroke.

Meanwhile, the doctor prescribed different medicines to see what might help. One didn't work at all; another made Donna upset and angry. Finally, the third medicine seemed to make her memory and reasoning better on the days she took it.

Donna didn't find what she wanted: some hope, another possibility, a reason to not believe. And during another round of testing a year later, in October 2010, when she couldn't explain what "don't count your chickens before they are hatched" meant, she says, "I just kind of snapped at that point."

"I hate hysterical, wimpy women. I tell myself, 'Don't be such a girl. If a problem comes up, just deal with it,'" Donna says. But she cried that day, for the first time.

Flitman's diagnosis was firm. On Dec. 9, 2010, he wrote simply, "Alzheimer's disease."

"When he first said it was Alzheimer's," Nick says, "I didn't know enough about it to be upset. I thought it was something you get when you are old, and I didn't know it was fatal. I felt really bad for Donna. I mean, wow, she was just handed a death sentence."

People think of Alzheimer's as a disease that strips memories, but it is a full-on assault on neurons in the brain. It starts with the cells that hold short-term memory, killing them systematically, irrevocably.

Clumps of protein plaques and tangled nerve fibers choke off pathways, first erasing small things, like what was for lunch yesterday, and working up to bigger ones, like names of loved ones. As the disease progresses, killing even more cells, the brain can no longer send messages to the body, telling it what to do, or even to keep breathing.

While people with Alzheimer's often die from stroke, pneumonia, heart disease and other ailments before the disease runs its full course, a brain severely damaged by Alzheimer's eventually shuts down the body.

Finding ways to cope

Donna worked around the disease as much as she could at first, trying to keep it from interrupting her life, finding coping mechanisms and backstops.

"There's a lot I can fake," she confides. "I can listen to a conversation, smile and nod, and they walk away, and I have no idea what we were talking about."

Nick is healthy now, but when he was in the hospital in December 2010 with prostate cancer, Donna took a picture of his room number with her cellphone. Her sister would drop her off to visit, and Donna would find her way to Nick's room by comparing the picture to the doorways until she found a match.

If Donna got lost when she was driving, she'd stop and call Nick, reading him street signs and describing what she saw around her, and he'd guide her to where she was going.

But then it got harder to pretend.

Donna worked at a secondhand-book store, Bookmans in Phoenix, a job she'd taken in October 2007 after 22 years in banking. She told Katie Downing, her manager, of her diagnosis.

Downing says Donna was an ideal employee: in at 6:30 a.m., efficient, fair and fast on her feet. It was some time before the effects of her disease began to show up on the job.

Nick began driving Donna to work so she didn't get lost on the way, and her sister would pick her up. She managed for a while. But then Donna started getting lost in the store, and began struggling to add columns of figures.

She left the bookstore in April.

"Not working was a big deal for me," says Donna, who has worked since age 16. Earning her own money meant independence.

Since leaving her job, the losses have multiplied, and quickly.

Flitman, Donna's doctor, says that early-onset Alzheimer's does seem to progress more rapidly. Some estimates are that it can disable younger patients in five to 10 years instead of the 10 to 15 years it typically takes in older patients.

Donna reaches out and touches the spines of the paperbacks on the bookcase behind her. Her mother taught her to read before she was even old enough to start school, and Donna delighted in reading everything out loud. Her mom would shush the little girl to keep her from reciting the graffiti on the New York subway.

"Reading fiction could totally involve me in a story, transport me," Donna recalls. And non-fiction? "Just a love of learning about people, about places, history. I just wanted to know. I could spend hours just wandering around a bookstore or library, just browsing."

But then, bit by bit, the magic receded. Donna could not read anymore.

"I'm not sure when I first noticed, but it was just taking me longer and longer to read something, and then it got where I'd read something and, a couple pages in, I'd realize I didn't really know what they were talking about, and I'd have to go back and start over," she says.

"I would flip back through the pages, trying to figure out who was who. It just didn't make sense to me, what I was reading."

Donna's brain still processes and understands the written word. She can read e-mail, Facebook status updates, parts of newspaper articles. But comprehension and her ability to remember and follow a thread continue to deteriorate.

And as more pieces of Donna's memory fall away, the lists she posts around the house get longer and more detailed to compensate. Instead of "Do laundry," one says, "Put clothes in washer. Add detergent. Start washer."

"One time I took the dirty clothes from the hamper and put them straight in the dryer and turned it on. When they came out, I was like, 'These clothes don't smell clean,'" Donna says. "I can't remember the steps anymore."

So a note on a kitchen cabinet says, "Dog food is on top shelf, cat food is on bottom shelf." There's a list by the front door, another in the bathroom and still another in the shower.

"If I just wing it, something is going to go wrong," Donna says.

Sometimes something goes wrong anyway.

In March, Donna was boiling eggs on the stove and forgot about them. Spike, their black Labrador, ran, whining, back and forth between the kitchen and the back room where Donna was until she followed him out, saw the smoke and snatched the pot off the stove.

Since then, Donna rarely cooks when Nick isn't home. She worries that she will forget again. Now she makes lunch in the microwave.

A well-meaning outsider, trying to help Donna cope or feel better, might offer suggestions. What about a simple cookbook? Or a timer, for instance?

"The trouble is you never know when something is going to stop working. It could be the day when I forget what the timer is for," Donna says.

One night at dinner a few months ago, Donna held her knife and fork loosely in her fingers and looked at Nick, her face blank. At some point, as the disease kills off more brain cells, Alzheimer's patients lose the ability to perform two-handed tasks.

For now, Nick cuts up her food and she eats with a fork or spoon. Eventually, Donna won't be able to hold silverware at all, and he will feed her.

At a restaurant, Donna decides what she'd like to eat, but Nick orders for her.

"If they ask me a lot of questions, it's hard for me to answer," Donna explains.

And when she gets up to use the restroom, Nick goes with her, waiting just outside the door.

"She can't always find her way there," he explains.

"Or back," she adds.

Donna may get confused about where she is or muddled by the line of stall doors and not be able to find the door that leads out. Sometimes Nick takes her into the men's room instead, directing her into a stall and standing guard.

When she comes out, she reaches for his hand.

"You're like an anchor," Donna tells him. "Nothing is really certain but you. I'm not letting go of you."

More than forgetting

When Donna has forgotten something, it's not like when you wonder where you left your keys or try to put a name to a familiar face, she explains.

"When I forget something, it's not like it's in there somewhere. When I forget something, it's like I never knew it."

In fact, the word "forget" is a bit of a misnomer for what happens in a brain affected by Alzheimer's. The word suggests that whatever it is that has been forgotten -- a name, a procedure, a story -- is still in there somewhere, waiting. It's not. Alzheimer's wipes it out completely.

Sometimes, as in Donna's case, the Alzheimer's wanders from its expected route, ricocheting into different areas of the brain simultaneously, impacting some areas but not others. Imagine the attack radiating unpredictably in multiple directions, like a star, instead of like a bulldozer slowly following a road.

That morning in March when Donna put on her shoes and didn't know how to tie the laces, she still knew how to turn on the computer, search the Internet for no-tie shoelaces and figure out where to buy them. Now neon-pink laces curl through the eyelets of her white sneakers like corkscrews, holding them snugly closed.

"Why did she forget that one thing but not the next five?" Nick asks. He shrugs.

"I don't know. Even the doctors don't know."

When Nick moved the paper towels from one spot to another in the kitchen, he put a note up in the old spot so Donna would be able to find them. After a few weeks, she knew where the paper towels were. But does she know the paper towels even moved, or did she just forget about the old spot? Nick doesn't know.

Donna listens, a small smile on her face. No, she doesn't remember it herself.

"It's like you are hearing the story for the first time, not reminiscing. They are telling you a story like you weren't there, and in a way you weren't."

Anyone who has had a loved one with Alzheimer's knows the sad, disheartening feelings that come from witnessing how much has been lost: skills, memories, a sense of time, of life lived.

But Donna says she doesn't have sad feelings about what she can't do anymore. Since the disease destroys brain cells, including the ones that control emotions, flattening some responses, Donna can't know for sure whether that's because she's come to accept the ramifications of the disease, or she simply can't rage about what is happening to her.

She suspects that the old Donna would have fought tooth-and-nail to keep driving, to tie her own shoes, to read a book, to stay independent. This Donna is different.

"It's like pieces of your brain just fall off, and you lose things you don't even know that you had," she says.

"I can't change it, so why am I going to sit around and feel sorry for myself, or cry, or bang my head against the wall? Those last few years, I won't even know. I figure, for me, I'll be dead before I'm dead.

"I am just enjoying life."

Still, as determined as Donna is to enjoy life, there are constant reminders of what she is losing.

As Nick's birthday on Sept. 30 approached, just 10 days before her own, Donna was in a panic: "I have always made a big deal out of birthdays. I couldn't do that this year."

She would buy cards -- always more than one -- gifts, hang a "Happy Birthday" banner and make a special meal.

But this year she didn't trust herself to follow a recipe to make a cake. She couldn't drive to the store for a present or remember to look for one while she was there with Nick.

Donna celebrated in a new way. She pulled up poems and pictures on the computer, printed them out and taped them up around the house. She printed a birthday card, too, and folded another piece of paper into an envelope.

"Losing the ability to do for your loved ones is the hardest for me," Donna says. "But instead of worrying I can't do as I used to, I need to focus on what I still can. At some point, it probably won't bother me at all."

In that sense, the disease is easier on her and harder on Nick.

"We can't build a life together. We still exist together, but there is no building a life because only one of us is playing the game. The other one keeps forgetting the rules and has to be told about it, and I feel bad about that because it is not fair to him," Donna says.

"In a way, I'm the one who gets off easy here."

'Twinkle in her eye'

Donna and Nick met through an online dating service in 2000. Nick picked her out because of her picture: "She had this twinkle in her eye."

Donna had always said she would get married "when pigs fly," so when they married on Jan. 13, 2006 -- Donna remembers the date perfectly -- Nick carried a tiny plastic pig with wings in his jacket pocket.

Donna may think she is getting off easy, but she worries about Nick. Not just because he works too much, but also that if he doesn't take good care of himself and something bad happens, who would take care of her? Nick is a prostate-cancer survivor and has diabetes. Donna knows it sounds selfish.

"I tell him that if he doesn't take care of himself and winds up in a wheelchair, chances are good that I could wheel him somewhere and leave him, and then forget where I left him," she says, smiling at Nick. He chuckles.

Despite their ability to be lighthearted, the ways in which Donna depends on Nick are endless. She knows that she turned 50 on Oct. 10, because Nick tells her. She knew she was having a birthday party, because Nick told her that, too. Her former co-workers and old friends, as well as new friends from the Alzheimer's Association, would be there.

"If they remember," Donna joked at the time.

She depends on Nick to tell her what game they are watching on television, what she had for lunch, and sometimes even whether she ate lunch.

That reminds Nick: "Did you put a patch on this morning?"

"I don't know. Maybe not," Donna says, and she puts her hand into the neck of her purple shirt to feel for a patch on her arm. No, she's not wearing one.

Nick gets out a patch that releases donepezil, a medicine that to a degree helps Donna with cognition, including memory, communication and reasoning. With Nick's insurance, the patches cost $90 for a box of 30. Studies have shown the patch can delay the need for nursing-home care by as much as 21 months.

Donna pats the patch onto her arm.

She also uses a food supplement, mixing it into scrambled eggs or soup to mask the taste, that acts as an energy source for brain cells and that is supposed to stimulate the front part of the brain. It seems to help, when she remembers to use it.

All her life Donna moved fast, chin up and not afraid. Now her steps are slow and careful, her eyes on the ground in case it shoots out from beneath her.

"Some days it is difficult to make my feet go forward. A lot of it is my depth perception is so bad, if I don't look carefully where I am going, either I feel all off-balance or I do fall."

Nick steadies her.

When unfamiliar places and faces make Donna anxious, it is the sight of Nick that makes her feel safe.

"What if he fell or was unconscious, will I know to call 911 for help? Maybe I will today, but what about later this week or a month from now?" Donna wonders.

And the worst thought of all: What if one day she doesn't recognize the man she loves?

"I hope that never happens," she says quietly.

Solace in the past

Each morning starts the same. Donna wakes up just before Nick leaves for work, confused about where she is and when it is.

One morning in October, she reached for her cat, Chloe, and grew concerned when she couldn't find her. She looked under the bed and in the closet and then she saw Biscuit, a little pug she didn't get until a few years after Chloe had died.

Donna cried as if it had just happened.

"It takes a little bit to orient myself, and some days it just never clears up. Disassociated, I guess, might be a good term. You just feel kind of like you're not sure exactly where you are. Things are like smoke, not really solid, just kind of out of step," she says. "It's like you've walked into a movie halfway through, and it's in a foreign language that you don't understand. You are not certain of anything."

On bad days, Donna looks different, her cheeks flushed, a faraway look in her eyes. It's as if someone pushed her pause button, or she's gone somewhere else. Sometimes she has.

"There are some days when I just keep drifting back to the past, not that I don't know where I am, but I get a lot more memories of the past, and that is kind of comforting in a way," Donna says.

One day last summer, Donna said to Nick, "All right. I give up. Where did you put the brown card table that used to be in the front closet?"

The couple have never owned a card table, but Donna's family had one when she was little.

When that happens, "To me, it's as real as this," she says, running her hand across the top of the kitchen island.

Things from her past -- the music, TV shows -- bring her solace.

"I think because the now is kind of a shifting landscape, and the past is still stable. That is when things were good and safe, and you were in control. There was nothing going on that you didn't understand. It is something solid that you can hold onto, though not really," Donna says. "That's what is so weird. It feels real and solid, but I know that it is not."

She won't always know that it is not real.

And when that does happen, Nick will pick up Donna's story and tell it for her.

"Here we were, planning for retirement, when we can stop working and start traveling and do all this fun stuff," Nick says, and then he pauses. "It's just like the door closed."

Instead, this fall the Bakers attended workshops called Early Stage Partners in Care, run by Arizona State University professor David Koon, and together they made tough decisions while Donna could still have a say.

She decided she would be all right with having someone come in to help care for her, but she does not want to go to a hospital-like nursing home with four patients in a single room.

She'd rather go to the kind of place where she can have her own room, though she knows that by that time she likely won't know where she is, or even care. She wonders what that part of the journey will be like, what she will be like.

"I think on some level the person is there, even if it doesn't seem like they are," she says.

Donna hopes that when she's that far along, and it seems as if she's not in there anymore, people will look hard to find the traces of her.

Nick will. He promises.

"I'm sad for her, for the things we're not going to be able to do together. I don't feel sorry for myself. I am just focused on her right now. I don't even think about me," Nick says. "We don't know how much time we are going to have."

Nick will do what is best for Donna, he says, but if there are questions later about what Donna wanted, he has it written in a book.

"It gives me confidence to make that decision or at least make the decision that is in her best interest," he says.

Another doctor's visit

Reading from a copy of her doctor's notes after a Nov. 15 appointment, Donna announces, "Well, I still have Alzheimer's. It says so on the paper."

"My gait is more apraxic, whatever that means," she reads. "Flat affect. Memory impaired for short term and intact for long term. Speech is coherent and fluent -- thank you very much."

She hadn't wanted to go back to the doctor this time.

"I felt things were about the same. I hadn't noticed any big change, and with Nick being so busy, I hate to add anything more to his plate," Donna says. "Honestly, what are they going to do? It's not like when you have an infection, and you go and get a shot and walk out and feel better."

Flitman asked her a series of questions.

The day of the week? Tuesday, she said. It was Wednesday.

What month it is? October, she thought. It was November, which Donna says wasn't bad considering she was going to say June but knew that wasn't right because she had just had her birthday.

What street is that? Thomas Road. It was Virginia Avenue, just south. Close enough, Donna says.

What floor are we on? The first, she said. Correct.

And the guy sitting next to her? That's Nick, and she added for good measure: "My husband."

Flitman wants to keep Donna on the same regimen -- the patches and food powder. Her next appointment is not for another six months, instead of the usual three or four. The Bakers take that as a good sign.

"It's moving along," Donna says.

In late November, Nick and Donna were eating breakfast out when he noticed she was holding her fork backward, trying to scoop up hash browns with the handle.

"She was just looking at it, like, 'What's the problem with this thing?'" Nick says.

He gently took it from her hand, turned it right side up and gave it back. Unfazed, Donna resumed eating. But Nick's throat was tight: "I was so mad at myself for not noticing sooner. I don't want her to struggle. I don't care for me, but I don't ever want her to be embarrassed."

It hasn't happened again.

But the bad days are starting to outnumber the good ones.

Changing expectations

During the holidays, Donna joked that Nick could give her the same gift again and again, and she wouldn't notice. But secretly, she hoped for a good Christmas.

Tinsel hung on the pre-lit tree but no ornaments. (They didn't get around to it.) She received two pairs of slippers. She got Nick two DVDs. He played board games with his son and her sister while Donna watched. They nibbled on cheese and crackers. And Donna was happy.

She knows that seems easy to say. She still has perspective, at least right now.

"What I do know is each day you are alive and each day there is someone who matters to you is a day that is a perfect day. No matter what difficulties you may face.

"Trite? Yes, in a way. But deep down, under all the pain and hurt and anger that the world dealt you a very unfair hand, is the truth that you have or had someone who loved you and who you loved. And that in itself is a great deal more than many people in the world get."

Donna doesn't dwell on the fact that Saturday "date days" have changed; they used to mean breakfast out, movies, museums or street festivals; now, she and Nick are more likely to sleep in and watch old episodes of "The Rifleman."

She doesn't spend much energy fretting about how she can't follow the thread of a baseball game now, even though the old Donna was a lifelong sports fan, tagging with her dad to Shea Stadium as a little girl and knowing team standings and player stats as an adult.

She watches those games, happy just to be with Nick. She wishes he could take time off work, so they could spend more time together while she still can enjoy it. But they can't afford for Nick to retire from his job as a delivery supervisor, with a once-a-week route to Wickenburg.

So when he drives the route, Donna goes with him. They eat lunch together at an ice-cream parlor, where Donna steps only on the white tiles of the black-and-white-tiled floor because, for some reason even doctors can't explain, she perceives the black tiles as holes.

Nick asks, "What was the name of that restaurant?"

Donna raises her eyebrows: "Why are you asking me?" And they laugh.

When Donna is not with him, Nick calls from the road and says, "I've got a surprise for you," and brings her a fancy cookie or a plastic Scooby Doo, her favorite cartoon character.

"I just hate knowing what's ahead of her," he says. "I'm just amazed that she doesn't sit around and cry some days. I haven't seen her do it yet."

Again, insight from the inside, Donna says, "You learn to appreciate what you have today, because you don't know how much time you have."

But as 2011 came to a close, marking another year since her diagnosis, Donna acknowledges the losses.

"The new year is supposed to be a time of new beginnings. I can't say I feel that way anymore. I know there have been changes this year, but, for the life of me, I couldn't tell you what I could do at this time last year versus now.

"Some days still flow just fine; other days, I struggle to know how to pronounce the words I want to say.

"My memory is much worse. How do I know? There are gaps in my day. Do I forget everything? Of course not. I don't like to focus on what is gone; there is still so very much I can and will do. But the truth is, I have a limited shelf life, and a new year just reminds me now that it is that much closer."

Diagnosed with early-onset Alzheimer's disease, Donna Baker worries about the toll it will take on her husband, Nick, who responds, "I'm sad for her."

More on this topic

About this story

In July, Donna Baker contacted Arizona Republic reporter Karina Bland in response to a column Bland wrote about losing her beloved uncle to early-onset Alzheimer's disease.

"Tell my story," Donna said. "It is important that people understand this disease."

At their first meeting, Donna looked at a stack of notes on a table, read a few lines and asked, "Did I do this?" You did, her husband told her.

Donna wrote on her laptop what she wanted to say about being diagnosed with early-onset Alzheimer's disease at age 48, printed out the pages and then forgot that she had done it.

"It's like someone is coming along behind me and erasing things as I go," she said.

Donna is among 500,000 people in the United States, or about 5 percent of those with Alzheimer's, who have early-onset Alzheimer's, meaning they were diagnosed before age 65.

Disclosures such as hers likely will become more common as the Baby Boomer generation ages and doctors get better at detecting the disease in its earliest stages. Because of that, a change in federal law last year allowed patients with early-onset Alzheimer's to more easily receive Social Security Disability Insurance and Supplemental Security Insurance.

Donna gave Bland access to her medical records and Facebook posts, invited her to her home and birthday party, and gave written permission for her doctor to talk about her case.

Each time Donna met with Bland, she could not remember her from the time before. Her husband put up notes to remind her that Bland would be calling, or coming over.